Aircraft having rotative sustaining means



June 20, 1939. P. CAMERON 2,163,432

AIRCRAFT HAVING ROTATIVE SUSTAINING MEANS v Filed Dec. 24, 1936 3 Sheets-Sheet l June 20, 1939. CAMERON v AIRCRAFT HAVING ROTATIVE SUSTAINING MEANS 3 Sheets-Sheet 2 Filed' Dec. 24, 1956 7 Camera c "Ill I II II June 20, 1939. P. CAMERON 2,163,482

AIRCRAFT HAVING RQTATIVE SUSTAINING MEANS Filed Dec. 24, 1936 3 Sheets-Sheet 3 Patented June 20, 1939 i I Q UNITED STATES PATENT OFFICE 2,163,482 AIRCRAFT HAVING ROTATIVE snsrnmmo MEANS Peter Cameron, Kelvinside, Glasgow, Scotland Application December 24, 1936, sonar No. 117,627 In Great Britain January 1, 1936 12 Claims. (Cl. 244-17) This invention relates to aircraft having susthe. telescopic support comprises a hollow memtaining means consisting of rotor blades which ber I, preferably of oval or aerofoil cross section, can be extended and retracted. provided with a fork 2 at one end which is adapt- During rotation the blades become flexed uped to be secured by means of a pin 3 or the like,

wardly, the degree of fiexure of each blade varysee Figure 8, to the rotor head 4 of an aircraft. 5 ing with the resistance encountered thereby. This hollow or" inner member is provided with For example, when the aircraft is. stationary another hollow member 5 of similar cross secand the blades are rotating, all the blades are tion, which is adapted to slide thereon and on flexed upwardly to the sameextent, assuming this hollow member the usual supports or ribs,

that there is no wind which would result in the not shown, are mounted,,on which the covering 10 blades encountering a varying resistance sufli- 6 of the blade is secured. cient to flex the blades. A collar or the like 1 is provided at the inner When the aircraft is travelling forwards the end if said outer hollow member, and this collar flexure of each blade in turn varies in accordance is 1 ovided with, in preference, two stops or the 5 with the position of the blade or air resistance like 8 which are pressed towards the inner memencountered. When the blades are advancing ber by means of springs 9. These stops. are adaptthey encounter substantial resistance and in coned to engage in holes or slots III in the inner memsequence are substantially flexed, and when the ber when the blade is extended tothe maximum blades are retreating and also when they are comradius, the stops then dropping into the slots in o mencing to advance the flexure is relatively small. the inner tube. The outer face of the stop is at When the blades are stationary, and also when right angles to the surface of the tube, thus holdthey are not flexed, there are no mechanical difing the blade from extending any further, but ficulties in extending and retracting them, but the inner edge of the stops is provided with a when the blades are rotating and their degree of sloping surface 8 so as to oifer no resistance to fiexure varies during each rotation the resistance the blade when being retracted into its unex- 5 ofiered by the flexed blades to extension and retended position. The compression in thesprings traction-is so great that it would be quite imposcan be regulated by the screws II. sible for the pilot to extend and retract the blades Mounted within the inner tube is a nut or the under such-conditions. like I 2- capable of sliding therein, in which an 0 The present invention has for its primary obinternal thread is provided which engages with a j t 0 P v e an whereby the P o can ex screwed rod l3 mounted in a suitable thrust beartend and retract the blades irrespective of the ing in the fork so as to prevent it from longitudidegree of flexure attained by the blades during nal movement. To this nut is secured a tube 14, their rotation. which totally encloses the portion of the screwed Further objects of the invention will become rod which projects outwards, and on the end 5 I apparent from the specification and are set forth' of this tube are provided two collars or the like in detail in the claims at the end thereof. l5, between which a thrust member or collar l6 One form of the invention will now be described rigidly fixed to the outer member 5 is located, by way of example with reference to the accom- Suitable resilient means such, for instance, as 40 panying drawings in which: 1 helical compression springs I1, encircle the tube 40 F r 1 is a p f the rotor head having l4 between the two collars and the thrust three blades. member, such that the blade can move to a cer- Figure 2 is a vertical section along the centre tain extent longitudinally on the inner member line of one blade in the e e positionwithout rotation of the screwed rod taking place,

5 Fi r 3 is h m Figure 2 in the retrac d and the screwed rod can move longitudinally to position. I a limited extent independently of the blade. Any F u 4 is a p t of a tu nal section other resilient means, such as oil bufi'ers or the of a blade on a larger scale. i like, may be employed.

Figure 5 is a cross section of the blade. The inner end of the screwed rod when. it

Figure 6 is a cross section of the collar on the jects into the fork, is provided with a slot which 50 tube. l is adapted to engage with a projection-in a mem- Fisur '7 is a horizontal section of Figure 6. ber mounted upon the end of a flexible member Figure 8 is a sectional elevation of the rotor to which rotational movement can be im-' head. I parted. By such means on rotation of the screw n the embodiment of the invention illustrated in one direction the blade will be extended and 5 then on rotation in the opposite direction the blade will be retracted to its unextended position. The blade may be retained in any intermediate position.

In Figure 1 the full lines show the blades in the extended position and the chain dotted lines show them in the retracted position.

In order to provide additional safety means so that the blade cannot be extended beyond the maximum radius .or cannot fly 011 should the screw or other means become detached, further stops 8 may be provided at different distances along the blade so that the stops drop into slots arranged in different positions. The slots may all be arranged so that all the stops act at the same maximum distance or so that the different sets of stops act one after the other, the additional sets being kept as a stand-by or reserve, and only used when one or. more sets fail to come into operation. Further, inspection holes, not shown, may be provided in the blade so that the stops may be inspected to see that they are in working order and then suitable covers or the like may be provided to cover up the inspection holes so as to leave a smooth surface.

When the blades of the aircraft are rotating and the machine is stationary, all the blades are flexed upwardly to the same amount, but directly the machine begins to travel horizontally the flexure of the blade varies in accordance with the position of the blade and when the blade is retreating, the flexure is at its minimum. When it is required to extend or retract the blades if the screw is rotated and the blade is very much flexed, the flexure will prevent the blade from being moved, or permit only a small movement thereof but immediately the blade attains the position where the fiexure is reduced the resilient means, which has the energy stored therein will move the blade out or in, and then during the rest of the revolution the energy is again stored so that when the fiexure is reduced the blade will which the blade has the minimum flexure, means may be provided whereby the screws may be rotated only in this position so that the drive of the screw will then only operate to extend or retract the blade in its position of minimum flexure, and by this means the resilient means may also'be eliminated.

The tube 14 which covers the screw member within the blade may be filled with oil so, as to form an oil bathto make the screw operable with' the least amount of friction, and any suitable means may be provided for refilling the tube with oil. V

The inner tube is left exposed without any blade thereon for a suitable distance near the rotor head, either by the blade not being retractedto the minimum radius or by arranging that the inner tube does not slide right into the outer tube. By this means the blade portion is clear of the rotor head. This enables the two or more blades to be folded back so that all lie parallel to one another and'point directly to the tail of the machine, and therefore reduce the width and overall length of the machine, thus making it much more convenient for handling or garage purposes.

The extension may be of any desired amount according to the size of the blade and the purpose for which it is to be used. Further, the inner and outer sliding members may be of any other form in cross section than that described as long as means are provided when of circular cross section to prevent them from rotating relatively to one another.

The rotor head, illustrated in Figure 8, is similar to that illustrated and described in my copending patent application of even date, and only such parts thereof will now be described as are necessary to show how, according to one arrangement, the screw threaded rods H! can be rotated to extend and retract the blades.

The rotor head 1 is mounted on a hollow shaft l8 by which the head is driven through a oneway drive 19 from any convenient source, or the head may rotate under the action of the rotating blades.

Located within a gear casing 20 mounted within therotor head, are three bevel wheels 2|, only one of which is shown, the axes of the three pinions being at right angles to that of the driving shaft. Each pinion is connected to a flexible connection H, which in turn makes a driving connection with one of the screw threaded rods l3, as above set forth.

Meshing with the bevel wheels 2| are two crown wheels 22 through which passes freely a hollow spindle 23. The crown wheels carry dog clutch members 24, while said spindle carries the complementary clutch members 25. Any suitable means are provided to move said spindle longitudinally so that one or the other of said crown wheels is clutched thereto and further means provided to lock said spindle against rotation, suitable means for effecting both operations being set forth in my said co-pending application.

When the rotor head 4 is rotating and the hollow spindle 23 moved axially so that the top or bottom crown wheel is locked thereto by a dog clutch, and when said spindle is prevented from rotating, it follows that the bevel wheels 2 I, which are carried round by the rotor head, must be rotated about their own axes. The bevel wheels then transmit their motion through the flexible connections H to the screw threaded rods I3 and thus extend or retract the blades.

When the blades are in the desired position-the spindle is moved axially so that both crown wheels are free, the drive to screw threaded rods being thereby stopped.

It will be understood that, from the above description, theinvention covers different methods and mechanisms for extending and retracting said blades without departing from the scope of the invention.

What I claim is:

1. For flying machines of the type set forth a rotor head, hollow radially extending members secured to said head, outer hollow members telescopic on said radially extending members, rotor blades secured to said outer members, a screw threaded spindle extending through each inner hollow member, a nut threaded on said spindle, a hollow rod carried by said nut and resilient means connecting said hollow rod and said outer hollow member together.

2. In a flying machine of the type set forth the combination including a rotor head, hollow radially extending members secured to said head, outer hollow members telescopic on said radially extending members, rotor blades secured to said outer members, a screw threaded spindle extending through each inner hollow member, a nut threaded on said spindle, a hollow rod carried by said nut, resilient means connecting said hollow rod and said outer hollow member together, articulated members connecting said blades to said rotor head, and means in said rotor head for rotating said screw threaded spindles.

3. For aircraft of the type set forth a rotor head, telescopic blade supports carried by said head, rotor blades carried'by said supports and means for moving said blades radially, said means including a device by virtue of which, when the aircraft is in flight and each blade flexed to .various degrees during its rotation, said means operates on each blade'in turn to move it radially, only when its flexure is relatively small.

4. For aircraft of the type set forth, a rotor head, telescopic blade supports carried by said head, rotor blades carried by -said supports and means for moving the said blades radially, said means including means for causing said first mentioned means to .cease to function on each blade in turn when the resistance due to flexure becomes too great and to function on each blade in turn during part of its rotation when its flexure is less.

5. For aircraft of the type set forth a rotor head, telescopic blade supports carried by said head, blades carried by said supports and means for moving said blades radially, step by step, said means including means by which when the aircraft is in flight each blade in turn can be moved radially step by step and only when the flexure of the blade caused by the air resistance is relatively small.

6. For aircraft of the type set forth a rotor head, telescopic blade supports carried by said radially and resilient means incorporated between the head and each blade, which resilient means, when the flexure of a blade is such that too great resistance is ofiered to its radial movement by reason of its flexure, takes up the move ment of the blade operating means and transmits same to the blade when its flexure is less.

'7. For aircraft of the type set forth a rotor head, telescopic supports carried by said head, rotor blades carried by said supports, screw means for extending and retracting the blades and resilient means incorporated between the blades and screw means, which resilient means permit the screws to rotate irrespective of the degree of flexure of any of the blades, and where the flexure is such that the blades offer too great resistance to the resilient means, the resilient means take up the movement and transmit same to the blades when their degree of flexure is less.

8. A rotor head for aircraft of the type set forth having hollow radially extending members secured to said head, outer hollow members telescopic with respect to said radially extending screw-threaded spindle of each blade, the construction being such that where the blades are flexed the movement of the screws is taken up by the resilient means which, when the blades are at a lesser flexure, then operate to extend or retract its blade.

9. A rotor head and blades for aircraft of the type set forth comprising the combination including a rotor head, hollow radially extending members. secured to said head, outer hollow members telescopic with respect to said radially extending members, rotor blades secured to said outer members, a screw-threaded spindle extending through each radially extending .hollow member, a nut threaded on said spindle, a hollow rod carried ing through each inner hollow member, a nut threaded on said spindle, a hollow rod carried by said nut, resilient means connecting said hollow rod and said outer hollow member together, ar-

ticulated members connecting said blades to said rotor head, rotatable means in said rotor head for rotating said screw threaded spindles and flexible means connecting the rotatable means to the said spindle.

11. For aircraft of the type set forth, a rotor head, telescopic blade supports carried by said head, rotor blades carried by said supports, and

means for moving said blades radially, said means including means whereby when in flight each blade can be moved radially and individually and solely during a part of the rotation of the blade.

12. The device as claimed in claim 4 in which there are means independent of the means for moving the blade radially which positively lock the blades. against further outward movement when they are at their maximum radius.

'. PETER CAMERON. 

